com.google.gwt.sample.userwatcher.client.ImageUtils.java Source code

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Here is the source code for com.google.gwt.sample.userwatcher.client.ImageUtils.java

Source

package com.google.gwt.sample.userwatcher.client;

import com.google.gwt.canvas.client.Canvas;
import com.google.gwt.canvas.dom.client.Context2d;
import com.google.gwt.canvas.dom.client.ImageData;
import com.google.gwt.dom.client.ImageElement;
import com.google.gwt.user.client.ui.Image;
import com.google.gwt.user.client.ui.RootPanel;

public class ImageUtils {

    public static ImageData cropImage(Image image, double sx, double sy, double sw, double sh) {

        Canvas canvasTmp = Canvas.createIfSupported();
        Context2d context = canvasTmp.getContext2d();

        canvasTmp.setCoordinateSpaceHeight((int) sh + 10);
        canvasTmp.setCoordinateSpaceWidth((int) sw + 10);

        ImageElement imageElement = ImageElement.as(image.getElement());

        double dx = 0;
        double dy = 0;
        double dw = sw;
        double dh = sh;

        // draw image to canvas
        context.drawImage(imageElement, sx, sy, sw, sh, dx, dy, dw, dh);

        // get image data
        double w = sw;
        double h = sh;
        ImageData imageData = context.getImageData(0, 0, w, h);

        canvasTmp.removeFromParent();

        return imageData;
    }

    public static ImageData scaleAndCropImage(Image image, double scaleToRatio, double sx, double sy, double sw,
            double sh) {

        Canvas canvasTmp = Canvas.createIfSupported();
        //RootPanel.get().add(canvasTmp);
        Context2d context = canvasTmp.getContext2d();

        double ch = (image.getHeight() * scaleToRatio) + 100;
        double cw = (image.getWidth() * scaleToRatio) + 100;

        canvasTmp.setCoordinateSpaceHeight((int) ch);
        canvasTmp.setCoordinateSpaceWidth((int) cw);

        ImageElement imageElement = ImageElement.as(image.getElement());

        // tell it to scale image
        context.scale(scaleToRatio, scaleToRatio);

        // draw image to canvas
        // s = source
        // d = destination     
        double dx = 0;
        double dy = 0;
        context.drawImage(imageElement, dx, dy);

        // get image data - if you go greater than the scaled image nothing will show up
        ImageData imageData = context.getImageData(sx, sy, sw, sh);

        return imageData;
    }

    /**
     * for debugging
     * 
     * @param imageData
     */
    public static void addImageToScreen(ImageData imageData) {

        Canvas canvasTmp = Canvas.createIfSupported();
        canvasTmp.setCoordinateSpaceHeight((int) imageData.getHeight() + 10);
        canvasTmp.setCoordinateSpaceWidth((int) imageData.getWidth() + 10);
        Context2d context = canvasTmp.getContext2d();

        context.putImageData(imageData, 0, 0);

        //flexTable.setWidget(r, c, canvasTmp);
        RootPanel.get().add(canvasTmp);
    }

    /**
     * image - an ImageElement object
     * 
      sx - the x coordinate of the upper-left corner of the source rectangle
      sy - the y coordinate of the upper-left corner of the source rectangle
      sw - the width of the source rectangle
      sh - the width of the source rectangle
      dx - the x coordinate of the upper-left corner of the destination rectangle
      dy - the y coordinate of the upper-left corner of the destination rectangle
      dw - the width of the destination rectangle
      dh - the height of the destination rectangle
        
     */
    public static ImageData scaleImage(Image image, double scaleToRatio) {

        //System.out.println("PanoTiler.scaleImag()e: scaleToRatio=" + scaleToRatio + " width=" + width + " x height=" + height);

        Canvas canvasTmp = Canvas.createIfSupported();
        Context2d context = canvasTmp.getContext2d();

        double ch = (image.getHeight() * scaleToRatio) + 100; // 100 is offset so it doesn't throw
        double cw = (image.getWidth() * scaleToRatio) + 100;

        canvasTmp.setCoordinateSpaceHeight((int) ch);
        canvasTmp.setCoordinateSpaceWidth((int) cw);

        ImageElement imageElement = ImageElement.as(image.getElement());

        // s = source
        // d = destination 
        double sx = 0;
        double sy = 0;
        double sw = imageElement.getWidth();
        double sh = imageElement.getHeight();

        double dx = 0;
        double dy = 0;
        double dw = imageElement.getWidth();
        double dh = imageElement.getHeight();

        // tell it to scale image
        context.scale(scaleToRatio, scaleToRatio);

        // draw image to canvas
        context.drawImage(imageElement, sx, sy, sw, sh, dx, dy, dw, dh);

        // get image data
        double w = dw * scaleToRatio;
        double h = dh * scaleToRatio;
        ImageData imageData = context.getImageData(0, 0, w, h); // this won't get the extra 100

        return imageData;
    }

    public static ImageData cropImage(ImageData imageData, double sx, double sy, double sw, double sh) {

        Canvas canvasTmp = Canvas.createIfSupported();
        canvasTmp.setStyleName("mainCanvas");
        Context2d context = canvasTmp.getContext2d();

        canvasTmp.setCoordinateSpaceHeight((int) imageData.getHeight() + 10);
        canvasTmp.setCoordinateSpaceWidth((int) imageData.getWidth() + 10);

        // draw image to canvas
        context.putImageData(imageData, 0, 0);

        // get image data
        //imageData = context.getImageData(0, 0, imageData.getWidth(), imageData.getHeight());
        ImageData newImageData = context.getImageData(sx, sy, sw, sh);

        return newImageData;
    }

}